Related Experiment Video
Updated: Jul 7, 2026
13:02
Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow
Published on: February 27, 2016
Ensemble tracking for 2D vector velocity measurement: Experimental and initial clinical results
L N Bohs1, B J Geiman, M E Anderson
1Dept. of Biomed. Eng., Duke Univ., Durham, NC.
Summary
Ensemble tracking is a novel ultrasound method improving velocity estimation by measuring motion over shorter intervals, reducing errors. This technique enhances accuracy for ultrasound speckle tracking in various applications.
Area of Science:
- Medical Imaging
- Ultrasound Technology
- Biomedical Engineering
Background:
- Traditional speckle tracking techniques in ultrasound face limitations in accuracy due to echo decorrelation over longer time and distance intervals.
- Estimating two-dimensional velocities accurately is crucial for various diagnostic applications, including blood flow assessment.
Purpose of the Study:
- To introduce and evaluate a new ultrasound method, ensemble tracking, for enhanced two-dimensional velocity estimation.
- To compare the performance of ensemble tracking against previous speckle tracking methods.
Main Methods:
- Ensemble tracking utilizes parallel receive processing and 2D pattern matching to analyze speckle translations between successive ultrasonic acquisitions.
- Sub-pixel speckle translations are estimated using interpolation of the tracking grid.
- The method was tested on a tissue-mimicking phantom at various transducer angles (0, 45, and 90 degrees) and beam spacings.
Main Results:
- Ensemble tracking demonstrated reduced errors and increased maximum measurable velocities compared to conventional methods.
- Measurements showed mean errors ranging from -4% to +11% across different beam spacings and transducer angles after amplitude normalization.
- Amplitude normalization significantly improved accuracy, particularly at 45 and 90 degrees transducer angles.
Conclusions:
- Ensemble tracking offers a more accurate and precise method for estimating two-dimensional velocities using ultrasound.
- The technique shows promise for clinical applications, with initial results demonstrating successful tracking of carotid artery blood flow.
Related Concept Videos
01:24Relative Motion Analysis - Velocity
A stroke engine has a slider-crank mechanism that converts rotational motion from the crank into linear motion of the slider or vice versa. This mechanism consists of three main parts: the crank, the connecting rod, and the slider.
When an external force is exerted, it sets the crank into a rotational movement. This, in turn, instigates the motion of the connecting rod, leading to what is referred to as a general plane motion. This process involves two key points - point A on the connecting rod...
When an external force is exerted, it sets the crank into a rotational movement. This, in turn, instigates the motion of the connecting rod, leading to what is referred to as a general plane motion. This process involves two key points - point A on the connecting rod...
01:12Average and Instantaneous Velocity Vectors
To calculate other physical quantities in kinematics, the time variable must be introduced. The time variable not only allows us to state where an object is (its position) during its motion, but also how fast it’s moving. The speed at which an object is moving is given by the rate at which the position changes with time. For each position, a particular time is assigned. If the details of the motion at each instant are not important, the rate is usually expressed as the average velocity v. This...
01:30Vector Functions and Motion: Problem Solving
Accurate position tracking is fundamental to the safe and effective operation of unmanned aerial vehicles (UAVs), particularly during precision maneuvers near complex structures. In this scenario, a drone is programmed to perform a high-precision inspection of a vertical structure, starting at position ((x, y, z) = (3, 0, 0)), with an initial velocity oriented in the positive z-direction. The trajectory of the drone is governed by a time-dependent acceleration function a(t), which is predefined...
01:11Relative Velocity in Two Dimensions
Relative velocity is the velocity of an object as observed from a particular reference frame, or the velocity of one reference frame with respect to another reference frame. The concept of relative velocity can be used to describe motion in two dimensions. Consider a particle P and two reference frames S and S′. The position of the origin of S′ as measured in S is , the position of P as measured in S′ is , and the position of P as measured in S is , which can be evaluated by utilizing vector...
01:31Motion in Space: Velocity and Acceleration
The motion of an object in space, such as a drone flying through the air, can be described mathematically using a position vector, denoted r(t), which specifies the object's location at any given time t. Analyzing the motion of the drone involves examining how this position vector changes over time.The average velocity over a time interval is obtained by dividing the change in position by the duration of the interval. As the interval becomes infinitesimally small, this average velocity...
01:34Velocity and Position by Graphical Method
Velocity and position can be calculated from the known function of acceleration as a function of time. The total area under the acceleration-time graph and the velocity-time graph gives the change in velocity and position, respectively. In the case of an airplane, its acceleration is tracked using the inertial navigation system. The pilot provides the input of the airplane's initial position and velocity before takeoff. The inertial navigation system then uses the acceleration data to calculate...